Novel Presentation-Attack Detection:
Novel class detection has been studied within several learning settings. The learning setting that we explore is more related to the zero-shot learning (ZSL) formulation [1]}, [2]}, [3]}, [4]}. ZSL has been studied extensively but works on ZSL for PAD have been quite limited.
Most ZSL works have proposed to identify novel classes using the standard semantic-based idea for describing a sample. In these works, it is assumed that the semantic description of a novel class is accessible a priori. Novel classes can then be identified by establishing relationships between known and unknown classes through their semantic descriptions. Note, however, coming up with accurate semantic descriptions for PAs is challenging.
